The present invention claims priority from Japanese Patent Application No. 11-72499 filed Mar. 17, 1999, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an equipment for use in an electronic conference through a communication circuit and, particularly, to a display switching technique for an image information for performing an electronic conference.
2. Description of the Related Art
In a multi-point video conference system for performing an electronic conference through a communication circuit, a conference terminal is provided in each of locations in which participants of a conference come together and a plurality of such conference terminals are connected to a multi-point control unit (MCU) provided on a center of the conference through the communication circuit. Each conference terminal collects an image information and audio information in a location in which the conference terminal is provided and transfers these information to the MCU. In the MCU, the image information and the audio information are synthesized and the synthesized information is distributed to the respective conference terminals. In each conference terminal, the image information from the MCU is displayed on a display device provided in the conference terminal and the audio information is outputted through a loudspeaker also provided in the conference terminal.
As prior arts related to such multi-point video conference system, Japanese Patent Application Laid-open Nos. H7-245753 and H6-86275 disclose techniques for selectively displaying one of a synthesized picture and a single picture. Further, Japanese Patent Application Laid-open Nos. H4-40790, H8-14944 and H5-103324 disclose techniques for changing a construction of a synthesized picture by a current speaker of a conference. Japanese Patent Application Laid-open No. H5-207456 discloses a technique for displaying statistics of the number of speeches.
However, there are problems in the conventional multi-point conference system, which will be described below.
A first problem of them is that, since, in order to switch a picture display between a synthesized picture and a single picture, a picture display condition selecting operation is required on the side of the conference terminal, it is impossible to adaptively control the picture display by the MCU correspondingly to a current situation of the conference. A second problem is that, since the picture display condition is determined by a current speaker even in a case where the picture display condition is to be changed according to a content of current speech, it is impossible to control the picture display condition correspondingly to a content of proceedings (report or discussion).
The present invention was made in view of the above mentioned state of the art and has an object to provide a multi-point video conference system in which it is possible to automatically control a picture display condition between a single picture display and a synthesized picture display adaptively to a content of proceedings of a conference without requiring an operation by a chairman or an operator of the conference.
Another object of the present invention is to provide a multi-point video conference system capable of constituting a picture display optimal to a situation of proceedings of a conference.
In a multi-point video conference system including a plurality of conference terminals each provided in a different one of a plurality of locations, particularly, a multi-point video conference system utilizing a multi-point control unit (MCU) having a picture synthesizing function, the present invention is featured by that a switching of picture display between a single picture and a synthesized picture can be automatically performed suitably according to a situation of proceedings, such as a situation in which a report is performed from one of the conference terminals or a discussion is performed between conference terminals, without requiring any operation of a chairman or an operator of the conference.
That is, in a multi-point video conference system including a plurality of conference terminals and a distribution unit for distributing video signals and audio signals outputted from the conference terminals to the respective conference terminals, the present invention is featured by that the distribution unit comprises a measuring unit for measuring speech times of the respective conference terminals, a selector unit for selecting one of the conference terminals, the speech time of which is the longest, according to a result of measurement by the measuring unit, a determination unit for determining whether or not the longest speech time of the conference terminal selected by the selector unit exceeds a suitable threshold value, and a display unit for displaying an video signal from the conference terminal having the longest speech time on display devices of the respective conference terminals simultaneously as a single picture when the longest speech time exceeds the threshold value and displaying video signals from the respective conference terminals on the display devices of the conference terminals simultaneously as a synthesized picture when the longest speech time is shorter than the threshold value.
With this construction of the multi-point video conference system, it is possible to automatically switch the picture display between a single picture and a synthesized picture, which is suitable for a situation of proceedings of the conference, without necessity of operation of a chairman or an operator of the conference.
Alternatively, the distributor unit may comprise a measuring unit for measuring speech times of the respective conference terminals, a permutation producing unit for producing a permutation of the conference terminals according to a length order of speech times measured by the measuring unit starting from the conference terminal having the longest speech time, a detector unit for detecting conference terminals having speech times exceeding a threshold value according to the conference terminal permutation produced by the permutation producing unit and a simultaneous display unit for displaying video signals from the respective conference terminals detected by the detector unit on display devices of the conference terminals simultaneously as a synthesized picture.
With this construction of the multi-point video conference system, it is possible to switch the picture display on the respective conference terminals between the single picture and the synthesized picture and, in the case of the synthesized picture, to select the conference terminal having long speech time and display the synthesized picture on the display devices thereof.
The simultaneous display unit may comprise means for simultaneously displaying video signals of all of the conference terminals on the respective conference terminals as the synthesized picture when the speech times of all of the conference terminals do not exceed the threshold value.
In a case where the number of the conference terminals is too large to display the video signals from all of the conference terminals simultaneously as a synthesized picture, the simultaneous display unit may further comprise a display unit for displaying video signals from a plurality (m) of conference terminals, which are selected in the length sequence of speech time according to the conference terminal permutation, on the display devices of the conference terminals simultaneously as a synthesized picture, where m is equal to or smaller than the total number of the conference terminals.
The simultaneous display unit may comprise a pattern selector for selecting one of a plurality of display patterns in response to an input operation of the one display pattern. With such construction, it is possible to display a picture suitable for a situation of the proceedings of the conference, in addition to the automatic switching of the picture according to the speech time.